Marin Katusa: The days of tossing another lump on the fire to keep warm are behind most of us, but coal is still vital to keep our modern computers, air conditioners, and even cars humming. How much do you know about one of the world’s most indispensable commodities?
#1. Before turning into coal, layers of ancient swamp bed transition through another familiar carbon compound in as little as 9,000 years. That’s peat.
In the right conditions, high pressures and temperatures below Earth’s crust can turn organic material from ages-old swampy sediments into coal. But before that happens, the material passes through an intermediate stage that the Irish made famous. Peat is coal in the making, and as most everyone knows, it burns too. (For connoisseurs among us of the single malt, peat also helps give Islay scotches their distinctive flavor.)
There are also different kinds of coal itself. They vary in their content of water, carbon, and other ingredients, and in the time it takes to fashion them as well. The hardest coal, called anthracite, requires on the order of millions of years to form. That’s a long way from peat.
#2. A single percentage-point improvement in the efficiency of a coal-fired power plant results in a 2-3% reduction in CO2emissions.
Facilities that convert coal into power currently generate 41% of the world’s electricity, according to the World Coal Association. At about 43%, the United States rates about average. But the world’s second-largest economy, China, depends on coal for 81% of its electricity; and with nearly as many people, India depends on coal for 68%. A few countries rely almost completely on burning coal to make power—South Africa (94%) and Poland (86%), for example.
Small surprise, then, that a lot of research has been devoted to reducing the carbon emissions and other pollutants that result from combusting coal. Once it’s mined, washing it to remove impurities can reduce ash by more than 50%, while also removing much of the sulfur that causes acid rain. Grinding lumps into powder makes the coal burn more efficiently as well as quickly. In smokestack exhaust, filters capture soot and more ash, and scrubbers capture mercury and more sulfur.
We’ve come a long way from Victorian London and its noxious yellow fog. But there are strong incentives to keep at it. The return on improvements is still significant, as you can see above.
Furthermore, coal’s vital role in power generation is likely to be around for a long time yet—most predictions even set it as increasing slightly in the next few decades. With all the talk about natural gas and alternative energies, coal still provides the always-on, baseload type of power that’s so hard to replace.